1. Field of the Invention
The present invention relates to a vehicle and a control method thereof, and particularly, to a vehicle including a grille shutter that adjusts an opening area of a radiator grille, and a control method thereof.
2. Description of Related Art
In order to cool off an engine and the like provided in a vehicle, external air is taken into an engine compartment during vehicle running. In order to adjust an amount of the external air to be taken in, a grille shutter is provided in a radiator grille that introduces the external air, and the grille shutter is opened and closed. If the grille shutter is broken and kept closed, a temperature in the engine compartment increases.
For example, Japanese Patent Application Publication No. 2012-197001 (JP 2012-197001 A) describes a grille shutter control, device that performs a driving control on a driving device that opens and closes a grille shutter provided, in an air introduction path that introduces air in front of a vehicle into an engine compartment. Herein, abnormality is detected based on a state after an operation of the grille shutter is started, and a user is informed by a pilot lamp based on the abnormality thus detected.
Japanese Patent Application Publication No. 5-58172 (JP 5-58172 A) suggests that, when an opening and closing operation of movable grilles for a radiator grille and a front cross member is performed between a fully opening state and a fully closing state, a cooling temperature of an engine is changed rapidly, so that engine performance may be decreased. Here, an opening and closing control is performed, according to a load condition of the engine, on two movable grilles, i.e., a first movable grille that takes in external air in front of a vehicle and a second movable grille that takes in external air below or beside the vehicle. It is described that when the engine load condition exceeds a predetermined value in a state where the first movable grille and the second movable grille are opened, an engine load is cut off.
Note that as a technique related to the present invention, Japanese Patent Application Publication No. 2007-71126 (JP 2007-71126 A) describes such a control device of an internal combustion engine that various fuel increase coefficients are added to a map in which a basic injection quantity of fuel is determined based on an air intake amount and an engine speed, according to driving conditions at the time of startup, transient operation, and the like. It is described that one of the fuel increase coefficients is an increase coefficient for restraining a temperature increase in an exhaust system component of the internal combustion engine.
As described in JP 2012-197001 A, when a close malfunction occurs in a grille shutter, a temperature in an engine compartment increases. This increases a temperature of a catalyst provided in an exhaust system of the internal combustion engine, which may cause an overheating state. When the temperature of the catalyst overheats, a catalytic action decreases, so that exhaust-gas purification performance decreases.